Keg pressure after carbonation

[Andrew Lawrence]

Hi all,

I kegged my first beer and it turned out great. I do however have a couple of questions that none of the guides I find online seem to answer;

- after the beer has carbonated to satisfactory levels, you drop it to ~10 psi to serve. After pouring a glass, Do you then have to crank it back up to the initial carbonation pressure(about 25psi for me), until you are ready to pour more glasses? If you leave it at serving pressure for an extended time will the beer eventually become flat?

- I have been returning my keg to 25 psi after every glass of beer I pour. I have not been disconnecting my liquid line because every time I do, a few drops run down the side of the keg from the post. I'm not worried about the lost beer but I don't want a mess and stink of fouled beer left in my keggerator. Is this a bad idea? There doesn't seem to be any leaks but the last thing I want is for my tap to burst off and fill my keggerator with 25psi beer foam.

Tia!

 

[VikeMan]

- after the beer has carbonated to satisfactory levels, you drop it to ~10 psi to serve. After pouring a glass, Do you then have to crank it back up to the initial carbonation pressure(about 25psi for me), until you are ready to pour more glasses?

No. Consult one of the dozens (hundreds?) of CO2 pressure vs temperature charts on the web. They all have the same numbers. They will tell you exactly what pressure you need to maintain "x" volumes of CO2 at a given temperature.

Here's one,
https://www.kegerators.com/carbonation-table/
Your 25 PSI was for burst (or "fast force") carbonating, not for equilibrium.

 

[Andrew Lawrence]

Thanks for the reply, but it doesn't answer my question. I am aware of carbonation charts. Let me clarify my question.. I need 25psi to get my desired carbonation for my wheat beer(its not super cold and I like it nice and bubbly). After reducing to serving pressure, should I return the keg to 25psi after every glass? Is it alright to leave it at serving pressure for half a day or will it start to go flat?

 

[camonick]

25 psi is approximately 2X higher than necessary for a normally carbonated beer. You will find that most people store and serve between 8 & 12 psi for most styles. You can leave it set at those pressures for the duration of the keg and your beverage line will need to be the appropriate ID and length to provide foam free pours.

Edit: posted after your above reply.
If you truly need that much pressure for your taste, you should leave it there to maintain equilibrium and use enough beverage line to balance the system, which could be upwards of 30’ of 3/16” tubing. I’ve never understood why people want to keep fiddling with pressure every time they want to pour a beer.

 

[VikeMan]

Thanks for the reply, but it doesn't answer my question. I am aware of carbonation charts. Let me clarify my question.. I need 25psi to get my desired carbonation for my wheat beer(its not super cold and I like it nice and bubbly). After reducing to serving pressure, should I return the keg to 25psi after every glass? Is it alright to leave it at serving pressure for half a day or will it start to go flat?

Serving at 10 PSI, over time it will move toward whatever the CO2 volumes are at equilibrium for 10 PSI and whatever temperature you're at. If you return it to 25 PSI, it will head back toward to your original volumes of CO2.

But the real solution is that if you intend to regularly serve beers that need 25 PSI to maintain your desired carbonation, you need a beer line with enough resistance to balance against that high pressure, i.e. a longer line, to slow down the pour. Then you won't have to fiddle with anything.

 

[DVCNick]

To answer your second question, a few hours at lower pressure won't flatten the beer in any detectable way.

My picnic tap is 5', so I set the keg to 3 psi or less any time I'm using it... Usually for several hours taking a keg to someone else's party. Beer is always fine. Just put to back to equilibrium pressure when you are done for the day.